Industrial truck



Oct. 31, 1939. E J. DUNHAM 2,178,369

INDUSTRIAL TRUCK Filed March 12, 1938 3 Sheets-Sheet 1 A TTORNEY.

E. J. DUNHAM INDUSTRIAL TRUCK Oct. 31, 1939.

3 Sheets-Sheet 2 Filed March 12, 1938 INVENTOR. 54/70? J flaw/m BY WWZM ATTORNEY- Oct. 31, 1939. E. J. DUNHAM 2,178,369

INDUSTRIAL TRUCK Filed March 12, 1938 3 Sheets-Sheet 5 1N VEN TOR. Z/75F (Xian/194m BY 7/MX A TTORNEY Patented Oct. 31, 1939 INDUSTRIAL TRUCK Elmer J. Dunham, Battle Creek, Mich., assignor to Clark Equipment Company,

Buchanan,

Mich., a corporation of Michigan Application March 12, 1938, Serial No, 195,460

11 Claims.

The present invention is directed to trucks of the finger lift type used for picking up and transporting boxes, cartons, skids and the like, or for lifting and tiering the same in industrial and mercantile establishments. 4

While trucks of the type known as finger lift trucks, in which two forwardly extending lift fingers are provided for moving under a load or the like, have been in use for some time, difficulty has been found in providing a truck which could be employed for lifting various sizes of boxes, cartons or the like in which the spacing was such that the fingers had to be shifted laterally in order to properly support the load. This was usually accommodated by employing means whereby the fingers could be independently adjusted laterally with respect to the supporting carriage, as clearly shown in my copending application, Serial No. 179,273, filed December 11,

However, this necessitated that the operator leave the truck, manually move the fingers to the required space, and then remount the truck and move into the desired position for lifting up the goods.

The present invention, in its broadest aspects, relates to a construction whereby a truck of this type may move into position for raising variously shaped boxes, commodities or the like without requiring that the fingers be manually adjusted for each size of package, carton or box which the machine is to lift. By means of the present invention I am able to move boxes, cartons and the like of various shapes and sizes without requiring the operator to dismount from the truck, and without requiring that the truck be centered with respect to the particular object which is to be lifted.

This is preferably accomplished by providing the lifting fingers with pivotal supports upon the load carriage and providing suitable means for producing relative lateral movement of the fingers to accommodate them to the various sizes of articles which it is desired to transport. The 45 means for varying the spacing of the fingers may be controlled hydraulically, pneumatically or mechanically, and in a preferred form of the invention I provide for accomplishing this control automatically through the suction present in the intake manifold in the engine which drives the truck.

One object of the present invention is to provide a truck of this type which has a pair of uprights rotatably mounted at their lower ends 5 on a driving axle, and which can be tilted either forwardly or rearwardly by suitable actuating means controlled by the operator. Mounted for vertical movement on the uprights I provide a load-supporting carriage, which may be raised or lowered and which is provided with the longi 5 tudinally extending fingers for engaging the ar-'- ticle to be lifted and transported. These fingers may be moved relatively to the carriage and to each other by the operator through suitable mechanism controlled from the operator's plat- 10 form, and this movement is independent of the position of the uprights or the position of the load-supporting carriage.

Another object of the present invention is to provide an adjustable finger mechanism for in- 15 dustrial trucks of this type in which pneumatic or hydraulic means is employed for moving the fingers laterally, and which is under the control or the operator so that the truck does not have to be centered with respect to the article to be 20 raised or lowered, but can approach the article in a longitudinally offset position.

A still further object of the present invention is to provide adjustable finger actuating means which is so arranged that the load is transferred directly to the carriage, and no appreciable bending stresses are imposed upon the pivots of the fingers.

Another feature of the present invention is the mounting of the actuating mechanism for the fingers within spaced protecting plates so that this mechanism is not exposed to possible damage due to contact with articles being lifted or the like.

Still another feature of the present invention is the provision of a simple control lever mounted adjacent the conventional control mechanism of a truck of this type, which is readily accessible to the operator for controlling the movement of the fingers and which operates independently of the operation of the tilting and raising mechanism.

In the form of the invention in which the suction of the intake manifold is employed for the actuation of the finger control mechanism, it will be apparent that no damage can occur due to the fingers pressing laterally inwardly upon a box or the like, since the suction is insuificient to produce any substantial pressure of this sort. 0

Other objects and advantages of the present invention will appear more fully from the following detailed description which, taken in conjunction with the accompanying drawings, will disclose to those skilled in the art the particular 55 construction and operation of a preferred form of the present invention.

In the drawings:

Figure 1 is a perspective view of a truck embodying the present invention;

Figure 2 is an elevational view, with portions broken away, of the finger actuating mechanism;

Figure 3 is a plan view of the structure shown in Figure 2;

Figure 4 is a diagrammatic view showing the mechanism for operating the actuating means by manifold suction;

Figure 5 is a view similar to Figure 4 for hydraulic operation of the mechanism; and

Figure 6 is a diagrammatic view showing a modification of the actuating mechanism employing only a single cylinder.

Referring now in detail to the drawings, I have disclosed in Figure l a truck embodying a frame 5 upon which is mounted an internal combustion engine (not shown) enclosed within the hood 6, and suitably connected thru a transmission and differential axle means to the drive wheels I as described in detail in my above-mentioned copending application.

Rotatably supported at their lower ends on the axle spindles, upon which the wheels 1 are rotatably mounted, are a pair of uprights 8 which are of generally channel shape and which, at their upper ends, are connected together by the cross frame member 3. On the rear portions of the uprights 8 adjacent the upper ends thereof, there IS provided brackets l which form suitable journal supports for a cross shaft 1 l to which are pivotaliy connected the thrust rods l2. The thrust rods l2 extend through suitable slots I3 in the hood 6 and into tilt cylinders rotatably mounted upon the frame adjacent the rear end thereof. The particular hydraulic arrangement and connections for actuating the thrust rods I2 to tilt the uprights 8 about their lower ends is described in detail in my copending application, Serial No. 190,714, filed February 16, 1938. As described in said copending application, a suitable control rod I4 is provided on one of the thrust rods l2 for controlling the limits of tilting movement of the uprights 8.

Mounted between the uprights adjacent the lower end thereof is a hydraulic cylinder indicated generally at I5 which is provided with a piston rod l6 projecting therefrom, and supporting a cross head I! which carries two laterally spaced sprocket wheels l8 over which are trained chains H! which are rigidly connected at one end to the back of the uprights 8 and at the opposite end are engaged to carry a load-supporting carriage indicated generally at 20. The carriage is preferably provided with a guiding portion including rollers adapted to be guided within the channel portions of the uprights 8 for controlling the vertical movement of the carriage upwardly and downwardly with respect to the uprights.

The plate 20 which forms the standard portion of the carriage is provided with projecting spacer members 22, as shown more clearly in Figure 3, upon which is mounted the protecting plate 23 which serves as a shield for protecting the pivotal mounting of the fingers and the actuating mechanism for moving the fingers. Interposed between the plates 23 and 20 are a pair of pivot studs 24, as shown more clearly in Figure 2, upon which are pivotally mounted the upper ends of the fingers 25. Suitable bosses welded or otherwise secured to the adjacent surfaces of the plates 23 and 20 form spacing members for holding the Journal portions of the fingers 25 in position axially of the studs 24, as indicated at 25. Each of the fingers 25 has at its lower end the projecting finger portion 2'! which is provided with an upper knife edge 23 upon which the load is adapted to be supported.

Extending substantially laterally from the fingers 25 and overlapping adjacent the center of the space between the plates 23 and 20 are a .pair of arms 23 which may be formed integral with the fingers 25, and which, at their upper ends, are provided with pivot studs 32 for connecting the arms to the upper ends of the piston rods 33. It will thus be apparent zhat vertical movement of the piston rods 33 results in rotative movement of the arms 29 about the studs 24, and thus provides lateral movement of the finger portions 2? to vary the lateral spacing therebetween.

Each of the piston rods 33 is adapted to extend into a corresponding cylinder 34, the cylinders being provided at their lower ends with brackets forming journal supports therefor upon the studs 35 extending between the plates 20 and 23. Thus it will be apparent that the cylinders are mounted for pivotal movement transversely between the plates so that they may follow the arcuate path of movement of the arms 22 during rotative movement of these arms about the studs 24.

The cylinders 34 are cross connected at their lower ends by means of the conduit 36, and are similarly cross connected at their upper ends by means of the conduit 31. One of the cylinders 34 is also connected at its upper end to a conduit 33 leading therefrom to one port of a valve member, indicated generally in Figure 4 at 33. The lower end of the same cylinder is provided with a conduit connection leading to another port in the valve 39.

The piston rods 33 are adapted to extend through suitable packing gland members 42 in the upper ends of each of the cylinders, and within the cylinders are provided with the piston assemblies indicated generally at 43 in Figure 2.

Considering now the operation of the mechanism for actuating the fingers, the valve 33 is preferably mounted on the operator's dashboard, which is located at the end of the vehicle opposite the uprights 8. Preferably, the valve is of the type having a rotatable plug member controlled by the lever 44 whereby rotation of the lever 44 from neutral position in one direction opens the connection between the conduit 38 and the conduit 45 connected to the intake manifold 45 of the engine of the truck, whereby suction is produced in the conduit 38 and consequently in the upper ends of the cylinders 34. Similarly, when the valve lever is turned in the opposite direction, the conduit 45 is connected with the conduit 40 through the valve 39, and consequently the lower ends of the cylinders are subjected to suetion.

Preferably, a bleeder opening is provided in the valve 39 to allow the conduit, not subjected to the engine suction, to be open to atmosphere so that the engine suction is thereby effective to move the piston rods 33 in the desired direction in response to the selected actuation of the lever 44.

It will be apparent that with this construction, the rotation of the fingers 25 is entirely independent of the raising or lowering of the carriage 20 or of the tilting of the uprights 8, and also,

the fingers can be adjusted from any intermediate position in either direction.

It should also be pointed out that due to the fact that manifold suction is employed for controllingthe movement of the fingers in the event that the fingers engage the sides of the article to be raised or transported, the suction is "not sufilcient to effect any crushing action since the fingers will merely remain stationary in abutting position.

Considering now again Figure 1, it will be noted that when the truck is moved toward boxes, such as shown diagrammatically at and 52, the finger portions 21 may be spread apart a sufficient distance so that the edges 28 thereof engage under the flanges 53 formed at the upper edges of the lower box 58. As the fingers move under these flanges, the raising mechanism of the truck may be actuated to raise the boxes, to tilt the same rearwardly and to transport the same to any desired location. Suitable bumper strips 54 are provided between the fingers 21 and are mounted on the spacers 22 disposed below the cylinders 34 on the plate 28. This prevents the boxes from moving past a predetermined point with respect to the fingers 21, and insures that the loads will be supported in the proper position on the fingers.

If it is desired to raise only the upper box 52, the load-supporting carriage is raised by actuation of the cross head l1 to a position whereby the fingers may move under the flanges 55 at the upper edge of the upper box 52. Consequently, this box may be picked up and transported independently of the box 58, and may be tiered or stored in any suitable manner. It will also be apparent that the truck does not have to necessarily be alined with the longitudinal axis of the boxes inasmuch as an off-center approach to the boxes will result in one of the fingers 21 engaging the lateral side of the box and then remaining stationary until the other finger reaches its engaging position. While this may result in the load being carried off center with respect to the vertical center of the load-supporting carriage, nevertheless, the articles may be picked up and transported in this manner and thereby eliminate the necessity of the operator taking extra precautions in order to line the truck up with the center of the articles to be picked up.

Considering now Figure 5, a similar structure is provided insofar as the cylinder and piston rod arrangement is concerned but the upper ends of the cylinders 34 are connected through the conduit 56 to a four-way valve 51 which has opposed ports thereof connected through the conduits 58 and 58 to the high and low pressure sides of an oil pump or the like, indicated at 60, which is mounted on and driven from the transmission of the engine on the truck. A similar conduit 62 is connected to the lower ends of the cylinders 34, and a control lever 63 is provided for controlling the valve member in the valve 51.

In the operation of the construction shown in Figure 5, rotation of the lever 63 in one direction places the conduit 56 in communication with the high pressure outlet conduit 58 of the pump 60, and simultaneously places the conduit 62 in communication with the return or low pressure conduit 59 of the pump. This results in fiuid under pressure being forced into the upper ends of the cylinders 34, and fluid under substantially nopressure, or even negative pressure, being withdrawn from the lower ends of the cylinders.

A reverse movement 63 from neutral position places the conduits 58 and 62 in communication for forcing fluid under pressure into the lower ends of the cylinders, and places the conduits 56 and 59 in communication for exhausting fluid from the upper ends of the cylinders to the low pressure side of the pump 60. Thus, with such a construction, hydraulic pressure may be employed for actuating the cylinders, and may be controlled by the operator directly from his position on the truck independently of the movement of the load-supporting carriage or uprights.

In the modified form of the invention shown in Figure 6, the two fingers 65 mounted on the bell cranks 66 which are pivotally supported on studs 24 in a manner similar to that described in Figure 2 are adapted to be actuated by a single cylinder 61. Each of the bell crank levers 66 has an extending arm portion 68 at the upper end is provided with elongated overlapping slots engaged by a suitable pin 18 carried by the piston rod 12 reciprocated within the cylinder 61. It will therefore be apparent that outward movement of the piston rod 12 with respect to the cylinder results in moving these fingers 65 toward each other, whereas inward movement of the rod 12 results in spreading the fingers 65 apart. The cylinder 61 is connected at its opposite ends by the conduits 13 and 14' to a source of suction such as described in connection with Figure 4, or to a source of fluid under pressure such as described in Figure 5.

It is therefore believed apparent that I have provided a structure which may be employed for picking up various sizes of articles or packages, and which is capable of adjustment to the various sizes without requiring any manual adjustment by the operator, but only the actuation of a control valve controlling the actuation of the pneumatic or hydraulic means which operates.

the fingers. The construction is simple in design and operation and may be installed on existing types of such trucks at relatively small additional cost.

I am aware that a number of changes may be made in the details of construction of various parts of the present structure without in any way departing from the underlying principles thereof, and I therefore do not intend to be limited except as defined by the scope and spirit of the appended claims.

I claim:

1. In combination, in a load-supporting carriage for a truck of the class described, a pair of spaced plate members, pivot studs therebetween, a pair of lift fingers pivotally mounted on said studs and having normally extending load engaging portions, arms connected to said fingers adjacent said pivots and extending between said plates with the ends thereof overlapping, and means connected to said ends of said arms and supported between said plates for rotating said arms to rock said fingers laterally toward and away from each other.

2. In combination, in a vertically movable load supporting carriage for a finger lift type of industrial truck, a pair of spaced plates, lift fingers pivotally supported at their upper ends between said plates and having load supporting portions extending normally from one of said plates, overlapping arms connected to said fingers and extending between said plates, and means pivotally .mounted between said plates and having reciprocatory elements engaging the ends of said arms to rock the fingers laterally about their pivots.

3. A load supporting carriage for an industrial truck comprising a pair of spaced plates, lift fingers pivotally mounted therebetween and having arm portions extending toward each other between said plates, the lower ends of said fingers having normally projecting load supporting portions, a piston connected to the free end of each arm portion, cylinders receiving said pistons and pivotally mounted between said plates, and means interconnecting corresponding ends of said cylinders.

4. A load supporting carriage for an industrial truck comprising a vertically movable carriage including a pair of spaced plates, lift fingers pivotally mounted therebetween and having arm portions extending toward each other between said plates, a piston and cylinder mounted in a vertical position on one of said plates between said fingers, elongated overlapping slots in the free ends of said arms, and a pin in said slots connected to the end of said piston.

5. A load supporting carriage for an industrial truck comprising a pair of spaced plates, lift fingers pivotally mounted therebetween and having arm portions extending toward each other, a pair of cylinders pivotally mounted at one end between said plates, a piston in each cylinder, and means connecting the extending end of each piston to an arm portion of one of said fingers.

6. A load supporting carriage for an industrial truck comprising a pair of spaced plates, lift fingers pivotally mounted therebetween and having arm portions extending towardeach other, a pair of cylinders between said plates pivotally mounted for swinging toward and away from each other, means interconnecting corresponding ends of said cylinders, fluid conduits connected to each end of one of said cylinders and connected to a source of suction, a valve controlling the suction imposed on said conduits, and piston means in said cylinders connected to said arm portions of said cylinders.

7. A load supporting carriage for an industrial truck comprising a pair of spaced'plates, lift fingers pivotally mounted therebetween and having arm portions extending toward each other, a pair of cylinders between said plates pivotally mounted for swinging toward and away from each other, means interconnecting corresponding ends of said cylinders, fiuid conduits connected to each end of one of said cylinders and connected to a source of fluid under pressure, piston means in said cylinders connected to said arm portions of said fingers, and valve means controlling the passage of fluid under pressure through said conduits.

8. In an industrial truck, a vertically movable load supporting carriage, L-shaped lift fingers having their upper ends pivotally mounted on said carriage and having parallel forwardly extending portions, and pressure controlled means pivotally mounted on said carriage for swinging said fingers about their pivots.

9. In combination, in an industrial truck, a-

load supporting carriage having spaced transverse plates, a pair of lift fingers pivotally mounted between said plates in laterally spaced relation, cylinders pivotally mounted between said plates intermediate said fingers, arms carried by said fingers and extending toward each other between said plates, and pistons in said cylinders connected to said arms for swinging said fingers about their pivots.

10. In combination, in an industrial truck, a load supporting carriage including spaced plates, a pair of lift fingers pivotally mounted between said plates in laterally spaced relation, arms on the pivot ends of said fingers extending toward each other between said plates and having adjacent overlapping ends, cylinder means mounted on said carriage intermediate said fingers and having vertically extending piston means connected to the ends of said arms, and pressure developing means connected to said cylinder means for reciprocating said piston means to rotate said arms conjointly toward and away from each other.

11. In combination, in an industrial truck, a load supporting carriage including spaced plates, a pair of lift fingers pivotally mounted between said plates in laterally spaced relation, arms on the pivot ends of said fingers extending toward each other between said plates and having adjacent overlapping ends, cylinder means mounted on said carriage intermediate said fingers and having vertically extending piston means connected to the ends of said arms, and vacuum control means connected to said cylinder means for reciprocating said piston means to rotate said arms conjointly toward and away from each other.

ELMER J. DUNHAM.

Eli 

